The present invention relates to an abrasive system, more precisely relates to an abrasive system, which is capable of simultaneously abrading both faces of each work piece.
The inventor of the present invention invented and filed an abrasive machine. The abrasive machine has been already disclosed in the Japanese Patent Gazette No. 10-202511.
The abrasive machine comprises: a carrier formed into a thin plate having a plurality of through-holes;
an upper abrasive plate and a lower abrasive plate pinching work pieces, each of which is provided in each through-hole, from an upper side and a lower side and abrading both faces of each work piece; and
a carrier driving mechanism moving the carrier, in a plane, along a circular orbit without spinning so as to move the work pieces, which are pinched between the abrasive plates, with respect to the abrasive plates, along circular orbits without spinning. Note that, the upper abrasive plate and the lower abrasive plate are capable of independently spinning.
However, in the conventional abrasive machine, the work pieces are not automatically fed and taken out.
Namely, the work pieces are manually fed into the through-holes of the carrier and manually taken out therefrom. By manually handling the work pieces, the work pieces are sometimes polluted and damaged. Further, manufacturing efficiency cannot be improved. Therefore, an abrasive system, which is capable of automatically handling the work pieces, has been required.
To properly abrade the work pieces in the through-holes of the carrier, a clearance between an outer edge of the work piece, e.g., a silicon wafer, and an inner edge of the through-hole is designed 1 mm or less. The carrier is the thin plate, so it is apt to be slightly waved. Further, there is carrier with a carrier holder. Therefore, it is difficult to correctly position the through-holes at predetermined positions, so that it is also difficult to automatically feed the work pieces into the through-holes and discharge therefrom with high accuracy.
An object of the present invention is to provide an abrasive, which is capable of automatically and efficiently feeding and discharging work pieces with high accuracy.
The abrasive system of the present invention comprises:
a carrier being formed into a thin plate having a plurality of through-holes;
an upper abrasive plate and a lower abrasive plate pinching work pieces, each of which is provided in each through-hole, from an upper side and a lower side and abrading both faces of each work piece;
a carrier driving mechanism moving the carrier, in a plane, along a circular orbit without spinning so as to move the work pieces, which are pinched between the abrasive plates, with respect to the abrasive plates, along circular orbits, without spinning;
means for stopping the movement of the carrier at a predetermined position, the stopping means being provided to the carrier driving mechanism; and
means for feeding and discharging the work pieces, the feeding-and-discharging means including:
an arm robot having a work holding unit, which is provided to a front end and capable of holding and releasing the work piece, the arm robot feeding the work pieces into the through-holes of the carrier, which is stopped at the predetermined position, and discharging the abraded work pieces therefrom; and
an image processing unit for recognizing shapes and positions of the through-holes of the carrier and the work pieces.
With this structure, the stopping means stops the carrier at the predetermined position, then the work pieces can be precisely positioned, by the image processing unit, in the through-holes of the carrier. Further, the work holding unit can be precisely coincided with the work pieces in the through-holes by the image processing unit, so that the work pieces can be automatically and efficiently fed into and discharged from the through-holes. Since the through-holes are correctly positioned by the stopping means, positioning control of the work holding unit can be easy.
In the abrasive system, the carrier driving mechanism may include a servo motor, and
the stopping means may include a control unit for controlling the servo motor. With this structure, the carrier can be correctly stopped at the predetermined position by a simple means.
The abrasive system may further comprise a carrier spinning mechanism for spinning the carrier about an axis. The carrier spinning mechanism may be capable of stopping the carrier at a predetermined angular position. With this structure, a plurality of work pieces can be moved to a predetermined position in order, so that the work pieces can be fed into and discharged from the through-holes by the arm robot whose stroke is short.
In the abrasive system, the arm robot may be a horizontal multi-joint robot, and
the work holding unit and a camera of the image processing unit may be provided to a front end of the horizontal multi-joint robot. With this structure, the shapes and the positions of the through-holes of the carrier and the work pieces can be simultaneously recognized, so that the work pieces can be efficiently fed and discharged.
In the abrasive system, the arm robot may be a vertical multi-joint robot, which is capable of taking out the work pieces, which are vertically arranged in a cassette, and vertically storing the work pieces into another cassette. With this structure, additional means for taking out and storing the work pieces is not required, so that the system can be simple and compact.